From 33f79e2acb7f9f042971829ad195f88b751d29e5 Mon Sep 17 00:00:00 2001
From: Matthew Rocklin <mrocklin@gmail.com>
Date: Mon, 7 Aug 2017 10:43:26 -0700
Subject: [PATCH] add missing algos.c

---
 geopandas/algos.c | 100 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 100 insertions(+)
 create mode 100644 geopandas/algos.c

diff --git a/geopandas/algos.c b/geopandas/algos.c
new file mode 100644
index 0000000000..63184a01e8
--- /dev/null
+++ b/geopandas/algos.c
@@ -0,0 +1,100 @@
+
+#include <geos_c.h>
+#include "kvec.h"
+#include "algos.h"
+#include <stdio.h>
+#include <time.h>
+#include <stdbool.h>
+
+typedef char (*GEOSPredicate)(GEOSContextHandle_t handle, const GEOSGeometry *left, const GEOSGeometry *right);
+typedef char (*GEOSPreparedPredicate)(GEOSContextHandle_t handle, const GEOSPreparedGeometry *left, const GEOSGeometry *right);
+
+
+typedef struct
+{
+    size_t n, m;
+    GEOSGeometry **a;
+} geom_vector;
+
+
+void strtree_query_callback(void *item, void *vec)
+{
+    kv_push(size_t, *((size_vector*) vec), (size_t) item);
+}
+
+
+GEOSSTRtree *create_index(GEOSContextHandle_t handle, GEOSGeometry **geoms, size_t n)
+{
+    GEOSSTRtree* tree = GEOSSTRtree_create_r(handle, n);
+
+    for (int i = 0; i < n ; i++)
+    {
+        if (geoms[i] != NULL)
+        {
+            GEOSSTRtree_insert_r(handle, tree, geoms[i], (void*) i);
+        }
+    }
+    return tree;
+}
+
+
+size_vector sjoin(GEOSContextHandle_t handle,
+                  GEOSPreparedPredicate predicate,
+                  GEOSGeometry **left, size_t nleft,
+                  GEOSGeometry **right, size_t nright)
+{
+    // clock_t begin, begin_1, begin_2;
+    // clock_t end, end_1, end_2;
+    // double time_spent = 0, time_spent_1 = 0, time_spent_2 = 0;
+
+    size_t l, r;
+    size_vector out;
+    kv_init(out);
+    size_vector vec;
+    kv_init(vec);
+    GEOSPreparedGeometry* prepared;
+
+    // begin = clock();
+
+    GEOSSTRtree* tree = create_index(handle, right, nright);
+
+    // end = clock();
+    // time_spent = (double)(end - begin) / CLOCKS_PER_SEC;
+    // printf("Create tree, %f\n", time_spent);
+    // begin = end;
+
+    for (l = 0; l < nleft; l++)
+    {
+        if (left[l] != NULL)
+        {
+            // begin_1 = clock();
+            GEOSSTRtree_query_r(handle, tree, left[l], strtree_query_callback, &vec);
+            // end_1 = clock();
+            // time_spent_1 += (double)(end_1 - begin_1) / CLOCKS_PER_SEC;
+
+            prepared = GEOSPrepare_r(handle, left[l]);
+
+            // begin_2 = clock();
+            while (vec.n)
+            {
+                r = kv_pop(vec);
+                if (predicate(handle, prepared, right[r])){
+                    kv_push(size_t, out, l);
+                    kv_push(size_t, out, r);
+                }
+            }
+            GEOSPreparedGeom_destroy_r(handle, prepared);
+            // end_2 = clock();
+            // time_spent_2 += (double)(end_2 - begin_2) / CLOCKS_PER_SEC;
+        }
+    }
+    // end = clock();
+    // time_spent = (double)(end - begin) / CLOCKS_PER_SEC;
+    // printf("Intersect, %f\n", time_spent);
+    // printf("query, %f\n", time_spent_1);
+    // printf("intersect, %f\n", time_spent_2);
+
+    GEOSSTRtree_destroy_r(handle, tree);
+    kv_destroy(vec);
+    return out;
+}